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Merge #1515

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1515: Trait environment r=matklad a=flodiebold

This adds the environment, i.e. the set of `where` clauses in scope, when solving trait goals. That means that e.g. in
```rust
fn foo<T: SomeTrait>(t: T) {}
```
, we are able to complete methods of `SomeTrait` on the `t`. This affects the trait APIs quite a bit (since every method that needs to be able to solve for some trait needs to get this environment somehow), so I thought I'd do it rather sooner than later ;)

Co-authored-by: Florian Diebold <flodiebold@gmail.com>
This commit is contained in:
bors[bot] 2019-07-09 07:50:18 +00:00
commit f59cd1a4a0
11 changed files with 286 additions and 119 deletions
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13
crates/ra_hir/src/db.rs
View File

@ -213,18 +213,11 @@ fn struct_datum(
#[salsa::invoke(crate::ty::traits::chalk::impl_datum_query)]
fn impl_datum(&self, krate: Crate, impl_id: chalk_ir::ImplId) -> Arc<chalk_rust_ir::ImplDatum>;
#[salsa::invoke(crate::ty::traits::implements_query)]
fn implements(
#[salsa::invoke(crate::ty::traits::solve_query)]
fn solve(
&self,
krate: Crate,
goal: crate::ty::Canonical<crate::ty::TraitRef>,
) -> Option<crate::ty::traits::Solution>;
#[salsa::invoke(crate::ty::traits::normalize_query)]
fn normalize(
&self,
krate: Crate,
goal: crate::ty::Canonical<crate::ty::ProjectionPredicate>,
goal: crate::ty::Canonical<crate::ty::InEnvironment<crate::ty::Obligation>>,
) -> Option<crate::ty::traits::Solution>;
}

2
crates/ra_hir/src/ty.rs
View File

@ -26,7 +26,7 @@
callable_item_sig, generic_defaults_query, generic_predicates_query, type_for_def,
type_for_field, TypableDef,
};
pub(crate) use traits::ProjectionPredicate;
pub(crate) use traits::{Environment, InEnvironment, Obligation, ProjectionPredicate};
/// A type constructor or type name: this might be something like the primitive
/// type `bool`, a struct like `Vec`, or things like function pointers or

10
crates/ra_hir/src/ty/autoderef.rs
View File

@ -52,6 +52,8 @@ fn deref_by_trait(
// FIXME make the Canonical handling nicer
let env = super::lower::trait_env(db, resolver);
let projection = super::traits::ProjectionPredicate {
ty: Ty::Bound(0),
projection_ty: super::ProjectionTy {
@ -60,9 +62,13 @@ fn deref_by_trait(
},
};
let canonical = super::Canonical { num_vars: 1 + ty.num_vars, value: projection };
let obligation = super::Obligation::Projection(projection);
let solution = db.normalize(krate, canonical)?;
let in_env = super::traits::InEnvironment { value: obligation, environment: env };
let canonical = super::Canonical { num_vars: 1 + ty.num_vars, value: in_env };
let solution = db.solve(krate, canonical)?;
match &solution {
Solution::Unique(vars) => {

69
crates/ra_hir/src/ty/infer.rs
View File

@ -27,9 +27,10 @@
use test_utils::tested_by;
use super::{
autoderef, method_resolution, op, primitive,
autoderef, lower, method_resolution, op, primitive,
traits::{Guidance, Obligation, ProjectionPredicate, Solution},
ApplicationTy, CallableDef, ProjectionTy, Substs, TraitRef, Ty, TypableDef, TypeCtor,
ApplicationTy, CallableDef, Environment, InEnvironment, ProjectionTy, Substs, TraitRef, Ty,
TypableDef, TypeCtor,
};
use crate::{
adt::VariantDef,
@ -165,6 +166,7 @@ struct InferenceContext<'a, D: HirDatabase> {
body: Arc<Body>,
resolver: Resolver,
var_unification_table: InPlaceUnificationTable<TypeVarId>,
trait_env: Arc<Environment>,
obligations: Vec<Obligation>,
method_resolutions: FxHashMap<ExprId, Function>,
field_resolutions: FxHashMap<ExprId, StructField>,
@ -188,6 +190,7 @@ fn new(db: &'a D, body: Arc<Body>, resolver: Resolver) -> Self {
var_unification_table: InPlaceUnificationTable::new(),
obligations: Vec::default(),
return_ty: Ty::Unknown, // set in collect_fn_signature
trait_env: lower::trait_env(db, &resolver),
db,
body,
resolver,
@ -328,51 +331,25 @@ fn insert_type_vars(&mut self, ty: Ty) -> Ty {
fn resolve_obligations_as_possible(&mut self) {
let obligations = mem::replace(&mut self.obligations, Vec::new());
for obligation in obligations {
match &obligation {
Obligation::Trait(tr) => {
let canonicalized = self.canonicalizer().canonicalize_trait_ref(tr.clone());
let solution = self
.db
.implements(self.resolver.krate().unwrap(), canonicalized.value.clone());
match solution {
Some(Solution::Unique(substs)) => {
canonicalized.apply_solution(self, substs.0);
}
Some(Solution::Ambig(Guidance::Definite(substs))) => {
canonicalized.apply_solution(self, substs.0);
self.obligations.push(obligation);
}
Some(_) => {
// FIXME use this when trying to resolve everything at the end
self.obligations.push(obligation);
}
None => {
// FIXME obligation cannot be fulfilled => diagnostic
}
};
}
Obligation::Projection(pr) => {
let canonicalized = self.canonicalizer().canonicalize_projection(pr.clone());
let solution = self
.db
.normalize(self.resolver.krate().unwrap(), canonicalized.value.clone());
let in_env = InEnvironment::new(self.trait_env.clone(), obligation.clone());
let canonicalized = self.canonicalizer().canonicalize_obligation(in_env);
let solution =
self.db.solve(self.resolver.krate().unwrap(), canonicalized.value.clone());
match solution {
Some(Solution::Unique(substs)) => {
canonicalized.apply_solution(self, substs.0);
}
Some(Solution::Ambig(Guidance::Definite(substs))) => {
canonicalized.apply_solution(self, substs.0);
self.obligations.push(obligation);
}
Some(_) => {
// FIXME use this when trying to resolve everything at the end
self.obligations.push(obligation);
}
None => {
// FIXME obligation cannot be fulfilled => diagnostic
}
};
match solution {
Some(Solution::Unique(substs)) => {
canonicalized.apply_solution(self, substs.0);
}
Some(Solution::Ambig(Guidance::Definite(substs))) => {
canonicalized.apply_solution(self, substs.0);
self.obligations.push(obligation);
}
Some(_) => {
// FIXME use this when trying to resolve everything at the end
self.obligations.push(obligation);
}
None => {
// FIXME obligation cannot be fulfilled => diagnostic
}
};
}

34
crates/ra_hir/src/ty/infer/unify.rs
View File

@ -1,8 +1,10 @@
//! Unification and canonicalization logic.
use super::InferenceContext;
use super::{InferenceContext, Obligation};
use crate::db::HirDatabase;
use crate::ty::{Canonical, InferTy, ProjectionPredicate, ProjectionTy, TraitRef, Ty};
use crate::ty::{
Canonical, InEnvironment, InferTy, ProjectionPredicate, ProjectionTy, TraitRef, Ty,
};
impl<'a, D: HirDatabase> InferenceContext<'a, D> {
pub(super) fn canonicalizer<'b>(&'b mut self) -> Canonicalizer<'a, 'b, D>
@ -105,22 +107,28 @@ fn do_canonicalize_projection_predicate(
ProjectionPredicate { ty, projection_ty }
}
pub fn canonicalize_ty(mut self, ty: Ty) -> Canonicalized<Ty> {
// FIXME: add some point, we need to introduce a `Fold` trait that abstracts
// over all the things that can be canonicalized (like Chalk and rustc have)
pub(crate) fn canonicalize_ty(mut self, ty: Ty) -> Canonicalized<Ty> {
let result = self.do_canonicalize_ty(ty);
self.into_canonicalized(result)
}
pub fn canonicalize_trait_ref(mut self, trait_ref: TraitRef) -> Canonicalized<TraitRef> {
let result = self.do_canonicalize_trait_ref(trait_ref);
self.into_canonicalized(result)
}
pub fn canonicalize_projection(
pub(crate) fn canonicalize_obligation(
mut self,
projection: ProjectionPredicate,
) -> Canonicalized<ProjectionPredicate> {
let result = self.do_canonicalize_projection_predicate(projection);
self.into_canonicalized(result)
obligation: InEnvironment<Obligation>,
) -> Canonicalized<InEnvironment<Obligation>> {
let result = match obligation.value {
Obligation::Trait(tr) => Obligation::Trait(self.do_canonicalize_trait_ref(tr)),
Obligation::Projection(pr) => {
Obligation::Projection(self.do_canonicalize_projection_predicate(pr))
}
};
self.into_canonicalized(InEnvironment {
value: result,
environment: obligation.environment,
})
}
}

12
crates/ra_hir/src/ty/lower.rs
View File

@ -317,6 +317,18 @@ pub(crate) fn type_for_field(db: &impl HirDatabase, field: StructField) -> Ty {
Ty::from_hir(db, &resolver, type_ref)
}
pub(crate) fn trait_env(db: &impl HirDatabase, resolver: &Resolver) -> Arc<super::Environment> {
let predicates = resolver
.where_predicates_in_scope()
.map(|pred| {
TraitRef::for_where_predicate(db, &resolver, pred)
.map_or(GenericPredicate::Error, GenericPredicate::Implemented)
})
.collect::<Vec<_>>();
Arc::new(super::Environment { predicates })
}
/// Resolve the where clause(s) of an item with generics.
pub(crate) fn generic_predicates_query(
db: &impl HirDatabase,

21
crates/ra_hir/src/ty/method_resolution.rs
View File

@ -7,7 +7,7 @@
use arrayvec::ArrayVec;
use rustc_hash::FxHashMap;
use super::{autoderef, Canonical, TraitRef};
use super::{autoderef, lower, Canonical, Environment, InEnvironment, TraitRef};
use crate::{
generics::HasGenericParams,
impl_block::{ImplBlock, ImplId, ImplItem},
@ -200,6 +200,8 @@ fn iterate_trait_method_candidates<T>(
mut callback: impl FnMut(&Ty, Function) -> Option<T>,
) -> Option<T> {
let krate = resolver.krate()?;
// FIXME: maybe put the trait_env behind a query (need to figure out good input parameters for that)
let env = lower::trait_env(db, resolver);
'traits: for t in resolver.traits_in_scope(db) {
let data = t.trait_data(db);
// we'll be lazy about checking whether the type implements the
@ -211,8 +213,8 @@ fn iterate_trait_method_candidates<T>(
let data = m.data(db);
if name.map_or(true, |name| data.name() == name) && data.has_self_param() {
if !known_implemented {
let trait_ref = canonical_trait_ref(db, t, ty.clone());
if db.implements(krate, trait_ref).is_none() {
let goal = generic_implements_goal(db, env.clone(), t, ty.clone());
if db.solve(krate, goal).is_none() {
continue 'traits;
}
}
@ -279,11 +281,12 @@ pub fn iterate_impl_items<T>(
/// This creates Substs for a trait with the given Self type and type variables
/// for all other parameters, to query Chalk with it.
fn canonical_trait_ref(
fn generic_implements_goal(
db: &impl HirDatabase,
env: Arc<Environment>,
trait_: Trait,
self_ty: Canonical<Ty>,
) -> Canonical<TraitRef> {
) -> Canonical<InEnvironment<super::Obligation>> {
let mut substs = Vec::new();
let generics = trait_.generic_params(db);
let num_vars = self_ty.num_vars;
@ -296,8 +299,8 @@ fn canonical_trait_ref(
.enumerate()
.map(|(i, _p)| Ty::Bound((i + num_vars) as u32)),
);
Canonical {
num_vars: substs.len() - 1 + self_ty.num_vars,
value: TraitRef { trait_, substs: substs.into() },
}
let num_vars = substs.len() - 1 + self_ty.num_vars;
let trait_ref = TraitRef { trait_, substs: substs.into() };
let obligation = super::Obligation::Trait(trait_ref);
Canonical { num_vars, value: InEnvironment::new(env, obligation) }
}

79
crates/ra_hir/src/ty/tests.rs
View File

@ -3003,6 +3003,85 @@ fn test(o: O<S>) {
assert_eq!(t, "&str");
}
#[test]
fn generic_param_env_1() {
let t = type_at(
r#"
//- /main.rs
trait Clone {}
trait Trait { fn foo(self) -> u128; }
struct S;
impl Clone for S {}
impl<T> Trait for T where T: Clone {}
fn test<T: Clone>(t: T) { t.foo()<|>; }
"#,
);
assert_eq!(t, "u128");
}
#[test]
fn generic_param_env_1_not_met() {
let t = type_at(
r#"
//- /main.rs
trait Clone {}
trait Trait { fn foo(self) -> u128; }
struct S;
impl Clone for S {}
impl<T> Trait for T where T: Clone {}
fn test<T>(t: T) { t.foo()<|>; }
"#,
);
assert_eq!(t, "{unknown}");
}
#[test]
fn generic_param_env_2() {
let t = type_at(
r#"
//- /main.rs
trait Trait { fn foo(self) -> u128; }
struct S;
impl Trait for S {}
fn test<T: Trait>(t: T) { t.foo()<|>; }
"#,
);
assert_eq!(t, "u128");
}
#[test]
fn generic_param_env_2_not_met() {
let t = type_at(
r#"
//- /main.rs
trait Trait { fn foo(self) -> u128; }
struct S;
impl Trait for S {}
fn test<T>(t: T) { t.foo()<|>; }
"#,
);
assert_eq!(t, "{unknown}");
}
#[test]
fn generic_param_env_deref() {
let t = type_at(
r#"
//- /main.rs
#[lang = "deref"]
trait Deref {
type Target;
}
trait Trait {}
impl<T> Deref for T where T: Trait {
type Target = i128;
}
fn test<T: Trait>(t: T) { (*t)<|>; }
"#,
);
assert_eq!(t, "i128");
}
fn type_at_pos(db: &MockDatabase, pos: FilePosition) -> String {
let file = db.parse(pos.file_id).ok().unwrap();
let expr = algo::find_node_at_offset::<ast::Expr>(file.syntax(), pos.offset).unwrap();

63
crates/ra_hir/src/ty/traits.rs
View File

@ -67,10 +67,33 @@ fn solve(
solution
}
/// A set of clauses that we assume to be true. E.g. if we are inside this function:
/// ```rust
/// fn foo<T: Default>(t: T) {}
/// ```
/// we assume that `T: Default`.
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub struct Environment {
pub predicates: Vec<GenericPredicate>,
}
/// Something (usually a goal), along with an environment.
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub struct InEnvironment<T> {
pub environment: Arc<Environment>,
pub value: T,
}
impl<T> InEnvironment<T> {
pub fn new(environment: Arc<Environment>, value: T) -> InEnvironment<T> {
InEnvironment { environment, value }
}
}
/// Something that needs to be proven (by Chalk) during type checking, e.g. that
/// a certain type implements a certain trait. Proving the Obligation might
/// result in additional information about inference variables.
#[derive(Clone, Debug, PartialEq, Eq)]
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub enum Obligation {
/// Prove that a certain type implements a trait (the type is the `Self` type
/// parameter to the `TraitRef`).
@ -93,44 +116,14 @@ pub struct ProjectionPredicate {
pub ty: Ty,
}
/// Check using Chalk whether trait is implemented for given parameters including `Self` type.
pub(crate) fn implements_query(
/// Solve a trait goal using Chalk.
pub(crate) fn solve_query(
db: &impl HirDatabase,
krate: Crate,
trait_ref: Canonical<TraitRef>,
trait_ref: Canonical<InEnvironment<Obligation>>,
) -> Option<Solution> {
let _p = profile("implements_query");
let goal: chalk_ir::Goal = trait_ref.value.to_chalk(db).cast();
debug!("goal: {:?}", goal);
let env = chalk_ir::Environment::new();
let in_env = chalk_ir::InEnvironment::new(&env, goal);
let parameter = chalk_ir::ParameterKind::Ty(chalk_ir::UniverseIndex::ROOT);
let canonical =
chalk_ir::Canonical { value: in_env, binders: vec![parameter; trait_ref.num_vars] };
// We currently don't deal with universes (I think / hope they're not yet
// relevant for our use cases?)
let u_canonical = chalk_ir::UCanonical { canonical, universes: 1 };
let solution = solve(db, krate, &u_canonical);
solution.map(|solution| solution_from_chalk(db, solution))
}
pub(crate) fn normalize_query(
db: &impl HirDatabase,
krate: Crate,
projection: Canonical<ProjectionPredicate>,
) -> Option<Solution> {
let goal: chalk_ir::Goal = chalk_ir::Normalize {
projection: projection.value.projection_ty.to_chalk(db),
ty: projection.value.ty.to_chalk(db),
}
.cast();
debug!("goal: {:?}", goal);
// FIXME unify with `implements`
let env = chalk_ir::Environment::new();
let in_env = chalk_ir::InEnvironment::new(&env, goal);
let parameter = chalk_ir::ParameterKind::Ty(chalk_ir::UniverseIndex::ROOT);
let canonical =
chalk_ir::Canonical { value: in_env, binders: vec![parameter; projection.num_vars] };
let canonical = trait_ref.to_chalk(db).cast();
// We currently don't deal with universes (I think / hope they're not yet
// relevant for our use cases?)
let u_canonical = chalk_ir::UCanonical { canonical, universes: 1 };

99
crates/ra_hir/src/ty/traits/chalk.rs
View File

@ -12,7 +12,7 @@
use ra_db::salsa::{InternId, InternKey};
use test_utils::tested_by;
use super::ChalkContext;
use super::{Canonical, ChalkContext, Obligation};
use crate::{
db::HirDatabase,
generics::GenericDef,
@ -218,6 +218,103 @@ fn from_chalk(db: &impl HirDatabase, projection_ty: chalk_ir::ProjectionTy) -> P
}
}
impl ToChalk for super::ProjectionPredicate {
type Chalk = chalk_ir::Normalize;
fn to_chalk(self, db: &impl HirDatabase) -> chalk_ir::Normalize {
chalk_ir::Normalize {
projection: self.projection_ty.to_chalk(db),
ty: self.ty.to_chalk(db),
}
}
fn from_chalk(_db: &impl HirDatabase, _normalize: chalk_ir::Normalize) -> Self {
unimplemented!()
}
}
impl ToChalk for Obligation {
type Chalk = chalk_ir::DomainGoal;
fn to_chalk(self, db: &impl HirDatabase) -> chalk_ir::DomainGoal {
match self {
Obligation::Trait(tr) => tr.to_chalk(db).cast(),
Obligation::Projection(pr) => pr.to_chalk(db).cast(),
}
}
fn from_chalk(_db: &impl HirDatabase, _goal: chalk_ir::DomainGoal) -> Self {
unimplemented!()
}
}
impl<T> ToChalk for Canonical<T>
where
T: ToChalk,
{
type Chalk = chalk_ir::Canonical<T::Chalk>;
fn to_chalk(self, db: &impl HirDatabase) -> chalk_ir::Canonical<T::Chalk> {
let parameter = chalk_ir::ParameterKind::Ty(chalk_ir::UniverseIndex::ROOT);
let value = self.value.to_chalk(db);
let canonical = chalk_ir::Canonical { value, binders: vec![parameter; self.num_vars] };
canonical
}
fn from_chalk(db: &impl HirDatabase, canonical: chalk_ir::Canonical<T::Chalk>) -> Canonical<T> {
Canonical { num_vars: canonical.binders.len(), value: from_chalk(db, canonical.value) }
}
}
impl ToChalk for Arc<super::Environment> {
type Chalk = Arc<chalk_ir::Environment>;
fn to_chalk(self, db: &impl HirDatabase) -> Arc<chalk_ir::Environment> {
let mut clauses = Vec::new();
for pred in &self.predicates {
if pred.is_error() {
// for env, we just ignore errors
continue;
}
if let GenericPredicate::Implemented(trait_ref) = pred {
if blacklisted_trait(db, trait_ref.trait_) {
continue;
}
}
clauses.push(pred.clone().to_chalk(db).cast());
}
chalk_ir::Environment::new().add_clauses(clauses)
}
fn from_chalk(
_db: &impl HirDatabase,
_env: Arc<chalk_ir::Environment>,
) -> Arc<super::Environment> {
unimplemented!()
}
}
impl<T: ToChalk> ToChalk for super::InEnvironment<T> {
type Chalk = chalk_ir::InEnvironment<T::Chalk>;
fn to_chalk(self, db: &impl HirDatabase) -> chalk_ir::InEnvironment<T::Chalk> {
chalk_ir::InEnvironment {
environment: self.environment.to_chalk(db),
goal: self.value.to_chalk(db),
}
}
fn from_chalk(
db: &impl HirDatabase,
in_env: chalk_ir::InEnvironment<T::Chalk>,
) -> super::InEnvironment<T> {
super::InEnvironment {
environment: from_chalk(db, in_env.environment),
value: from_chalk(db, in_env.goal),
}
}
}
fn make_binders<T>(value: T, num_vars: usize) -> chalk_ir::Binders<T> {
chalk_ir::Binders {
value,

3
crates/ra_ide_api/src/change.rs
View File

@ -295,8 +295,7 @@ macro_rules! sweep_each_query {
hir::db::TraitDatumQuery
hir::db::StructDatumQuery
hir::db::ImplDatumQuery
hir::db::ImplementsQuery
hir::db::NormalizeQuery
hir::db::SolveQuery
];
acc.sort_by_key(|it| std::cmp::Reverse(it.1));
acc